Cycling system for respirator



May 27, 1969 METIVIER 3, 7

CYCLING sYsTEui FOR RESPIRATOR Filed Dec. 22, 1966 Sheet or 2 y 2 1969 R. METIVIER 3,446,207

CYCLING SYSTEM FOR RESPIRATOR Filed Dec. 22. 1966 Sheet 2 of 2 Z 6L l,

United States Patent 3,446,207 CYCLING SYSTEM FOR RESPIRATOR Robert Metivier, 49 Rue du Docteur Blanche, Paris 16, France Filed Dec. 22, 1966, Ser. N 0. 603,923 Claims priority, application France, Dec. 28, 1965,

Int. Cl. A62b 7/00; F17d 3/00 U.S. c1. 12s 14s.s

4 Claims This invention relates to a generator of periodic fluid signals which is applicable notably to the control of a respiratory mask.

Automatic respiratory apparatus are already known which are connected between a source of compressed gas (air or oxygen) and a respiratory mask. These apparatus operate periodically by utilizing the pressure of the compressed gas and during each cycle of operation they produce a forced inspiration following by an expiration phase.

All hiherto known apparatus of this type are designed according to the principle of the interconnection of pneumatic members having different structures, whereby these apparatus are characterized as a rule by a complicated and costly structure.

It is the essential object of the present invention to avoid this inconvenience by providing an apparatus adapted to be constructed in a particularly simple manner.

To this end, this generator of periodic fluid signals fed to a utilizing device, notably a respiratory mask, characterized in that it comprises a plurality of pneumatically controlled valves each having an inlet, an outlet and a control inlet, each valve being closed or open according as a fluid signal is respectively fed or not to the control inlet thereof, a first valve having its inlet connected to a source of fluid under pressure, its outlet connected to the utilizing device, its control inlet connected to the outlet of a second valve; this second valve having its inlet connected to the source of fluid under pressure and its control inlet connected to the outlet of a third valve having its inlet connected to the outlet of a fourth valve; a first pneumatic time-lag device connected between the outlet of said fourth valve and the control inlet of said third valve; the inlet of said fourth valve being connected to said source of fluid under pressure and its control inlet connected to the outlet of a fifth valve; the inlet of Said fifth valve being connected to the outlet of said second valve and a second pneumatic time-lag device connected between the outlet of said second valve, that is, the inlet of said fifth valve, and the control inlet of said fifth valve.

Immediately as the fluid under pressure is introduced into the circuit the generator of fluid signals according to this invention will cyclically transmit fluid to the utilizing device during time intervals corresponding to the opening time of said first valve during each cycle, the supply of fluid to said utilizing device being subsequently discontinued during the last fraction of each cycle, as long as said first valve is closed.

The utilizing device may advantageously consist of a respiratory mask. In this case the generator of periodic fluid signals according to this invention permits of supplying gas to this mask at a constant and adjustable frequency for producing a predetermined rate of the respiratory cycle and a constant ratio between the inspiration and expiration times of each cycle.

The generator of fluid signals according to this invention is advantageous notably in that its construction is remarkably simple and economical since it consists of standard component elements, that is, five valves of the same type and two pneumatic time-lag devices interconnected through pipe lines.

In order to afford a clearer understanding of this invention and of the manner in which the same may be carried out in practice, reference will now be made to the accompanying drawings illustrating diagrammatically by way of example a typical form of embodiment of the invention. In the drawings:

FIGURE 1 is a diagram showing the principle of a generator of periodic fluid signals according to this invention, as applied to the pneumatic supply of a respiratory mask;

FIGURE 2 is a diagram of the pneumatic time-lag device;

FIGURE 3 is a section illustrating diagrammatically a typical form of embodiment of a pneumatically controlled valve adapted to be used in the present invention.

The generator of periodic fluid signals according to this invention, as illustrated in FIGURE 1, is connected between a source A of fluid under pressure and a utilizing device B consisting in this example of a respiratory mask. In this specific application is is assumed that the generator is intended for supplying gas under pressure to the respiratory mask 2 during a first predetermined portion of the cycle which corresponds to the inspiration, and that this supply of gas is to be subsequently discontinued during the remaining portion of the cycle.

The generator of periodic fluid signals comprises five pneumatically controlled valves 1, 2, 3, 4 and 5 and two pneumatic time-lag devices 6 and 7. The pneumatically controlled valves 1 to 5 have all the same logical function and comprise each a supply inlet 2, and outlet .9 and a control inlet c. When no fluid signal (the pressure being at a low level or value is fed to the control inlet c of a valve, the latter is open and its inlet 0 communicates with its outlet s. On the other hand, when a fluid signal (high-level pressure) is fed to the control inlet c, the communication between the inlet e and outlet s is discontinued and the valve is closed. A specific form of embodiment of a pneumatically controlled valve of the type set forth hereinabove is illustrated in FIGURE 3. As the principle of operation of this type of valve is well known, it is not deemed necessary to describe it in greater detail.

The inlet of valve 1 is connected to the source A of gas under pressure through a pipe line 8 in which a needle valve 9 is inserted for adjusting the throughput. The outlet s of valve 1 is connected to the respiratory mask B via another pipe line 11 connected to a safety or relief valve 12.

The control inlet c of valve 1 is connected via a pipe line 13 to the outlet s of valve 2, via another pipe line 14 to the inlet e of valve 5 and via another pipe line 15 to a throttling device 7a provided at the inlet end of the pneumatic time-lag device 7. On the other hand, a non-return valve 16 is connected in parallel to this pneumatic time-lag device 7 having its outlet connected via a pipe line 17 to the control inlet c of valve 5.

The inlet e of valve 2 is connected through a pipe line 18 to the main supply line 8 connected in turn to the source of gas under pressure A and its control inlet 0 is connected through a pipe line 19 to the outlet s of valve 3.

The inlet e of valve 3 is connected to the outlet s of valve 4 having an inlet e connected via a pipe line 21 to the source A of gas under pressure. The outlet of this valve 4 is also connected through a pipe line 22 to a throttling device 6a disposed at the inlet end of time-lag device 6 having its outlet end connected through a pipe line 23 to the control inlet 0 of valve 3. A non-return valve 24 is connected in parallel to the time-lag device 6.

Finally, the control inlet c of valve 4 is connected through a pipe line 25 to the outlet s of valve 5.

The above-described device constituting the subjectmatter of this invention operates as follows:

When the source of gas under pressure A is connected to the circuit through valve means (not shown), the gas flows through line 8 and valve 1, the latter being open'since no pressure is applied to its control inlet c. This gas flows through line 11 into the respiratory apparatus B and follows therein the path shown by the thick-line arrows. This corresponds to the beginning of the inspiration or insufllation phase of the cycle.

When the source A of gas under pressure is connected to the circuit, gas will flow also through pipe line 21 and valve 4, the latter being open since no pressure is applied to its control inlet 0. The gas from the outlet s of the valve 4 is fed to the inlet e of valve 3 and simultaneously to the inlet throttling device 6a of time-lag device 6. As the valve 3 is open at that time, a pressure is produced at its outlet s and applied to the control inlet of valve 2. Thus, this valve 2 is closed and no pressure is produced at its outlet s and at the control inlet 0 of valve 1. All these operations take place practically instantaneously when the supply source A is connected to the circuit.

After a predetermined time period has elapsed, this period depending of course on the capacity of the time-lag device 6 and also on the cross sectional passage area of the throttling device 6a, a pressure develops at the outlet end of this time-lag device 6 and is transmitted via the pipe line 23 to the control inlet of valve 3. The latter is thus closed and the pressure applied to the control inlet 0 of valve 2 is eliminated. Under these conditions the valve 2 is open and gas flows through its outlet s. The pressure applied to the control inlet 0 will thus increase to close valve 1. At this time the gaseous stream produced in pipe line 11 is discontinued and the insufliation is stopped. The expiration then follows and the expired gas follows the path shown by the dash-line arrows.

The gas pressure produced at the outlet s of valve 2 is transmitted to the inlet throttling device 7a of time-lag device 7 and also to the inlet 2 of valve 5. As the latter is open, the gas pressure is transmitted to the control inlet c of valve 4, thus causing the closing of this valve 4. As a consequence of an interlocking effect, the closing of valve 4 is attended by the holding of valve 2 in its open position.

When the gas under pressure appears at the inlet throttling device 7a of time-lag device 7, it takes a certain time for this gas to fill the capacity of this time-lag device. After a time period depending on the capacity of time-lag device 7 and on the cross sectional passage area of throttling device 7a, a pressure develops at the outlet of time-lag device 7 and is transmitted via pipe line 17 to the control inlet 0 of valve 5. Then this valve 5 is closed and causes the valve 4 to open and therefore eliminates the pressure applied to the control inlet 0 thereof. The opening of valve 4 is attended by the opening of valve 3, the closing of valve 2 and the reopening of valve 1. The cycle can then be resumed with a fresh insufliation or inspiration phase.

FIGURE 2 illustrates diagrammatically the manner in which the operating frequency can be adjusted. It will be seen that the capacities of time-lag devices 6 and 7 are bounded by corresponding pistons 6b and 7b having their positions adjustable simultaneously by means of a control device 26. The smaller these capacities, the higher the operating frequency, and vice-versa.

If it is desired to maintain an equal ratio 1:1 between the two expiration and inspiration phases, the volumetric capacity of time-lag device 7 will be selected to be twice that of time-lag device 6.

Of course the specific form of embodiment illustrated and described herein should not be construed as limiting the scope of the invention since many modifications and variations may be brought thereto without departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim is:

1. Generator of periodic fluid signals applied to a utilizing device, notably a respiratory mask, which comprises a source of fluid under pressure, first, second, third, fourth and fifth pneumatically controlled valves having each an inlet, an outlet and a control inlet, each valve being closed or open according as a fluid signal is respectively applied or not to the control inlet of the valve, the inlet, outlet and control inlet of said first valve being connected respectively to said source of fluid under pressure, to said utilizing device and to the outlet of said second valve, the inlet of said Second valve being connected to the source of fluid under pressure and the control inlet of said second valve being connected to the outlet of said third valve, the inlet, outlet and control inlet of said fourth valve being connected respectively to the source of fluid under pressure, to the inlet of said third valve and to the outlet of said fifth valve, a first pneumatic time-lag device connected between the outlet of said fourth valve and the control inlet of said third valve and a second pneumatic time-lag device connected between the outlet of said second valve which is connected to the inlet of said fifth valve, and the control inlet of said fifth valve.

2. Generator as set forth in claim 1, wherein each pneumatic time-lag device comprises an adjustable capacity and a throttling device disposed at the inlet of said capacity.

3. Generator as set forth in claim 2, comprising means for simultaneously adjusting the volumes of the capacities of both time-lag devices whereby a constant ratio is constantly maintained between said two volumes.

4. Generator as set forth in claim 3, wherein each time-lag device comprises a cylinder, a piston movable in said cylinder for bounding a variable-volume chamber, and means for simultaneously displacing the pistons of both time-lag devices through a same distance.

References Cited UNITED STATES PATENTS 3,265,061 8/1966 Gage 128145.8 3,339,545 9/1967 Burchell 128-145.8 3,369,204 2/1968 Davis 137--624.18 XR L. W. TRAPP, Primary Examiner.

US. Cl. X.R. 137624.14 

1. GENERATOR OF PERIODIC FLUID SIGNALS APPLIED TO A UTILIZING DEVICE, NOTABLY A RESPIRATORY MASK, WHICH COMPRISES A SOURCE OF FLUID UNDER PRESSURE, FIRST, SECOND, THIRD, FOURTH AND FIFTH PNEUMATICALLY CONTROLLED VALVES HAVING EACH AN INLET, AN OUTLET AND A CONTROL INLET, EACH VALVE BEING CLOSED OR OPEN ACCORDING AS A FLUID SIGNAL IS RESPECTIVELY APPLIED OR NOT TO THE CONTROL INLET OF THE VALVE, THE INLET, OUTLET AND CONTROL INLET OF SAID FIRST VALVE BEING CONNECTED RESPECTIVELY TO SAID SOURCE OF FLUID UNDER PRESSURE, TO SAID UTILIZING DEVICE AND TO THE OUTLET OF SAID SECOND VALVE, THE INLET OF SAID SECOND VALVE BEING CONNECTED TO THE SOURCE OF FLUID UNDER PRESSURE AND THE CONTROL INLET OF SAID SECOND VALVE BEING CONNECTED TO THE OUT- 